Comparison of Observed and Predicted Abutment Scour at Selected Bridges in Maine

Lombard, Pamela J.; Hodgkins, Glenn A.

doi:10.3133/sir20085099

Cited by 7 publications

(5 citation statements)

References 12 publications

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“…Dey and Barbhuiya (2004b) suggested that K ó can be determined using a graph of K ó versus ó g : It can be seen that the presented K ó is in agreement with the results obtained by Dey and Barbhuiya (2004b). Table 5 shows the error measures of PR2 and the previous formulas for field data collected by Lombard and Hodgkins (2008). The l/y values in this dataset vary from 0 to 244 .…”

supporting

confidence: 86%

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Prediction of scour at abutments using piecewise regression

Etemad‐Shahidi

Rohani

2014

Proceedings of the Institution of Civil Engineers - Water Manag

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Scour is one of the main causes of bridge failure and scour depth prediction is thus a very important issue. Although many studies have been carried out to develop formulas for the prediction of scour depth at abutments, the existing formulas do not yield accurate results, mainly due to the complexity of the scour phenomena around abutments.This paper reports on a study of abutment scour using piecewise multiple linear regression analysis. First, scour depth data were collected from the literature and the existing formulas were evaluated and compared. To develop new formulas, the conventional governing parameters were selected as the independent variables. The piecewise multiple linear regression technique was applied to investigate the relationship between dimensionless scour depth and the governing dimensionless parameters in several subdomains. Errors of the proposed formula and previous models were also compared. Compared with existing formulas, the error measures in the proposed method show a significant improvement in prediction accuracy.

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supporting

confidence: 86%

“…In addition, the range of ó g shows that most of the experiments were conducted using uniform sediments and the d 50 ranges indicate that both fine and coarse sediments were studies. In addition, 100 field measurements collected by Lombard and Hodgkins (2008) from different bridges were used in this study.…”

Section: Description Of Datasetsmentioning

confidence: 99%

Prediction of scour at abutments using piecewise regression

Etemad‐Shahidi

Rohani

2014

Proceedings of the Institution of Civil Engineers - Water Manag

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“…All the field data compiled from the literature review were collected by the USGS. The field data included 15 measurements from the USGS National Bridge Scour Database (NBSD) (3,9); 92 from moderate-gradient streams of the South Carolina Piedmont with cohesive sediments (8); 106 from low-gradient streams of the South Carolina Coastal Plain (none are tidally influenced), generally with sandy, noncohesive sediments (8); 93 from small, steep-gradient streams in Maine with coarse sediments (5); and 23 from low-gradient streams in the Alabama Black Prairie Belt, with cohesive sediments (10). [The Alabama data were originally classified as contraction scour (10).…”

Section: Field Datamentioning

confidence: 99%

“…The complexity of abutment scour processes has made it difficult to formulate prediction methods, and few would dispute the above assessment by Ettema et al (1). Current scour prediction equations largely consist of semiempirical relations developed from simplified laboratory investigations (2), and the performance of these equations can vary (3)(4)(5). While overprediction occurs frequently (and at times excessively), underprediction also is of concern.…”

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confidence: 99%

Upper Bound of Abutment Scour in Laboratory and Field Data

Benedict

2016

Transportation Research Record: Journal of the Transportation R

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The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a field investigation of abutment scour in South Carolina and used those data to develop envelope curves that define the upper bound of abutment scour. To expand on this previous work, an additional cooperative investigation was initiated to combine the South Carolina data with abutment scour data from other sources and evaluate upper bound patterns with this larger data set. To facilitate this analysis, 446 laboratory and 331 field measurements of abutment scour were compiled into a digital database. This extensive database was used to evaluate the South Carolina abutment scour envelope curves and to develop additional envelope curves that reflected the upper bound of abutment scour depth for the laboratory and field data. The envelope curves provide simple but useful supplementary tools for assessing the potential maximum abutment scour depth in the field setting.

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“…These data were collected in part to form a database to evaluate the performance of scour-prediction equations and to understand abutment-scour trends in the field setting. Currently available USGS abutment-scour data include 208 measurements in South Carolina (Benedict, 2003) Wagner and others, 2006), and 100 measurements in Maine (Lombard and Hodgkins, 2008). The South Carolina database was the primary source for developing the original (Benedict, 2003) clear-water abutment-scour envelope curves and also served as the primary data source for developing the modified envelope curves in this investigation.…”

Section: Selected Field Data Used In the Analysismentioning

confidence: 99%

Modification of selected South Carolina bridge-scour envelope curves

Benedict¹,

Caldwell²

2012

Scientific Investigations Report

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Historic scour was investigated at 231 bridges in the Piedmont and Coastal Plain physiographic provinces of South Carolina by the U.S. Geological Survey in cooperation with the South Carolina Department of Transportation. These investigations led to the development of field-derived envelope curves that provided supplementary tools to assess the potential for scour at bridges in South Carolina for selected scour components that included clear-water abutment, contraction, and pier scour, and live-bed pier and contraction scour. The envelope curves consist of a single curve with one explanatory variable encompassing all of the measured field data for the respective scour components. In the current investigation, the clear-water abutment-scour and live-bed contraction-scour envelope curves were modified to include a family of curves that utilized two explanatory variables, providing a means to further refine the assessment of scour potential for those specific scour components. The modified envelope curves and guidance for their application are presented in this report. Description of Study Area South Carolina has an area of about 31,100 square miles (mi 2) and is divided into three physiographic provinces-the Blue Ridge, Piedmont, and Coastal Plain. The Coastal Plain province is divided into upper and lower regions (fig. 1). The study area for this investigation includes most of South Carolina but generally excludes the Blue Ridge and the tidally influenced area of the lower Coastal Plain. The Piedmont covers about 35 percent of South Carolina and lies between the Blue Ridge and Coastal Plain (fig. 1). Land-surface elevations range from about 400 feet (ft) near the Fall Line (Coastal Plain boundary) to about 1,000 ft at the Blue Ridge boundary. The general topography includes rolling hills, elongated ridges, and moderately deep to shallow valleys. The drainage patterns are well developed with well-defined channels and densely vegetated floodplains. Streambed slopes in the Piedmont range from approximately 0.00015 to 0.0100 foot per foot (ft/ft) (Guimaraes and Bohman, 1992). The geology of the Piedmont generally consists of fractured crystalline rock overlain by moderately to poorly permeable silty-clay loams. Alluvial deposits along the valley floors generally consist of clay, silt, and sand, and form varying degrees of cohesive soils (Guimaraes and Bohman, 1992). The stream-channel sediments typically consist of sandy materials overlying decomposed rock or bedrock.

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Comparison of Observed and Predicted Abutment Scour at Selected Bridges in Maine

Abstract: Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Cited by 7 publications

References 12 publications

Prediction of scour at abutments using piecewise regression

Prediction of scour at abutments using piecewise regression

Upper Bound of Abutment Scour in Laboratory and Field Data

Modification of selected South Carolina bridge-scour envelope curves

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